In a conventional elevator door control apparatus disclosed in, for example, JP 3-256992 A, a voltage monitoring circuit monitors a power supply voltage of a door driving motor, and forcible braking means brakes the door driving motor when an abnormality in the power supply voltage is detected.
However, in a door control apparatus as described above, when an abnormality occurs in the voltage monitoring circuit itself, for example, an output signal of the monitored result is fixed to the side indicating a normal state, the voltage cannot be monitored normally until that abnormality is eliminated.
Therefore, application of a conventional monitoring system to essential components of elevator control apparatuses such as an operation control unit and a safety unit is insufficient in reliability.